That's development stuff and most of us probably don't do development stuff (nothing to do with ITIL, for example). I last did development stuff in the early 80s.

Have you looked on Wikipaedia?_________________"Method goes far to prevent trouble in business: for it makes the task easy, hinders confusion, saves abundance of time, and instructs those that have business depending, both what to do and what to hope."
William Penn 1644-1718

The V model is part of service transition, consisting of a series of levels that details configuration stages and the testing/validation of them.
Perhaps to detailed to be explained, but is fully documented within the ITIL 3 Service Transition publication.